In order to form color photographic images, it is well known that an exposed photographic light-sensitive material having light-sensitive layers containing photographic couplers for three colors of yellow, magenta and cyan respectively is subjected to color development processing using a so-called color developing agent. In this process, a colored dye is formed upon a coupling reaction of a coupler with an oxidation product of an aromatic primary amine.
Color photographic images thus formed are required to show good preservability under various conditions. In order to satisfy this requirement, it is of importance that dyes used in forming each of the different hues show a slow color fading or discoloring rate and that the dyes show a discoloring rate as uniform as possible all over the image density region not to make the color balance of the remaining dye image unbalanced.
With conventional light-sensitive materials, particularly color papers, cyan dye images are seriously deteriorated by long-time dark fading due to the influence of humidity and heat and, hence, they are liable to undergo a change in color balance, thus a strong need has been felt that these materials be improved.
As hitherto known, there is the conflicting tendency with respect to cyan dye images that cyan images of less fading due to influence of humidity and heat show poor hue and remarkable fading due to influence of light and on the contrary, cyan images of less fading due to influence of light are liable to fade by influence of humidity and heat. Therefore, to develop a technique for simultaneously solving fading of cyan dye images due to influence of light, humidity and heat leads to remarkable improvement in not only preservability of cyan dye images but also preservability of balance of color images formed, thus the development of such a technique has been strongly desired.
In recent years, various kinds of improvements in techniques have been proposed in order to solve such problems. For instance, an improved technique using a coupler dispersing oil as described, for example, in JP-A-59-105645, JP-A-60-205447, JP-A-62-129853 and JP-A-62-196657 (the term "JP-A" as used herein means an "unexamined published Japanese patent application"), an improved technique involving a combination of couplers as described, for example, JP-A-60-221752, JP-A-60-221753, JP-A-60-242457, and JP-A-61-27540, an improved technique using a discoloration inhibitor as described, for example, in JP-A-60-222853, JP-A-62-87961, JP-A-62-118344, JP-A-62-178962, and JP-A-62-210465, and an improved technique using a combination of a coupler dispersing oil and a discoloration inhibitor as described, for example, in JP-A-61-167953, and JP-A-62-198859 have been proposed. However, these techniques are only partially effective or effective on a low level, and it can be seen that a satisfactory technique has not yet been developed.